SA-193 Gr. B7 Retightening

[Shmulik]

Hello all.
Is there any code (or other) restriction for bolting material SA-193 Gr. B7 Retightening?

 

[metengr]

No. This is a process detail. However, good engineering practice would require the following for re-use;

1. Visual examination of the bolt and threads to check for galling or damaged threads - if damage is found, discard.

2. If (1) is acceptable, perform a surface NDT (wet MT or Liquid Penetrant) or even a UT if the bolt is large enough to ensure no cracks - if cracks are found discard.

We have re-used (re-stretched) many B7 bolts because of service conditions where corrosion or creep was not a concern. If the bolts are properly stretched, they can be removed and re-used.

 

[XL83NL]

There is a post construction code providing guidelines on this matter; ASME PCC-1 appendix N.

 

[Shmulik]

Thanks for your prompt response!